2. Let’s Get Cooking with Moles! HH Br H H H2H2 +Br 2 HBr molecules4 x 10 -24 g320 x 10 -24 g2 (162 x 10 -24 g) Dozen molecules 4.8 x 10 -23 g384 x 10 -23 g2(194 x 10 -23 g) Molar mass 2 g160 g2(82 g) 2 +

3. The weight of a MOLE of one type of atom is equal to the atomic mass of that element in grams. Examples: Q: What is the weight of one mole of sulfur?A: 32.066 g Q: What is the weight of 0.5 mole of argon?A: 19.974 g Q: How many dozen are there in 6 nails?A: 0.5 dozen Q: How many moles are there in 6 g of carbon?A: 0.5 mol Q: How many moles are there in 1 g of H 2 ?A: 0.5 mol

5. 1.What is the gfm of water? 2. How much does one mole of water weigh? 3. How many moles are in 22.5 g of water? 4. How much would 1.5 moles of water weigh? Formula: H 2 O 1 mole H 2 O = 2(H) + 1(O)= 2(1.008 g) + 15.999 g =18.015 g 18.015 g/mol #mol = 22.5 g H 2 O/(18.015 g/mol)= 1.25 mol H 2 O Wt. H 2 O = (1.5 mol)(18.015 g/mol)= 27.022 g H 2 O

6. 5. How many molecules of water are there in 1.5 moles? 6. How many moles of NaCl are there in 2 x 10 22 formula units of NaCl? 7. How many atoms are in 2.0 moles of chlorine gas? Just like a dozen of something contains 12 of those somethings, one MOLE of something contains 6.022 x 10 23 of those somethings. #molecules = (1.5 mol)(6.022 x 10 23 m’cules/mol) = 9 x 10 23 m’cules Mol NaCl = (2 x 10 22 form.u)/(6.022 x 10 23 form.u/mol) = 0.033 mol NaCl Atoms Cl = (2.0 mol Cl 2 )(6.022 x 10 23 m’cules/mol)(2 atoms/m’cule) = 2.4 x 10 24 Cl atoms Cl 2 

7. 8. What is the volume of 2.0 moles of hydrogen gas at STP? 9. How many moles are there in 50 L of helium gas at STP? Mole Town can also be used to convert between moles and volume of a gas at standard temperature and pressure (STP). (STP = 273 K (0  C) and 1 atm pressure) Volume = (2.0 mol H2)(22.4 L/mol)= 44.8 L H 2 Mol He = (50 L)/(22.4 L/mol)= 2.23 mol He